title: Distinct genetic aberrations in oesophageal adeno and squamous carcinoma.
abstract: BACKGROUND
  The two main oesophageal cancer subtypes namely adenocarcinoma and squamous cell carcinoma exhibit interesting clinical, pathological and geographical variations with the former being more common in the West and the latter in Asia.
  
  
  METHODS
  We evaluated status of p53, EGFR, Wnt and HPV in addition to microsatellite instability and loss of heterozygosity of several chromosomal loci in the two oesophageal cancer subtypes from India. The comparative analysis was extended to two oesophageal adenosquamous mixed cancer samples.
  
  
  RESULTS
  Our results reveal a high frequency of EGFR overexpression in ESCC as against EAC, while Wnt activation was a significantly more common event in EAC as against ESCC. Frequencies of p53 perturbations were not significantly different in the two subtypes. Interestingly, the EGFR and Wnt status in adenocarcinoma and squamous components of the two oesophageal adenosquamous cancer samples were identical to primary tumours. In addition, no common molecular aberration (including instability and loss of heterozygosity) in several microsatellites was detected in DNA isolated from the two components in both adenosquamous cancer samples.
  
  
  CONCLUSIONS
  Our results reveal the presence of distinct aberrations in oesophageal adenocarcinoma and squamous cell carcinoma which are replicated in the respective components of adenosquamous cancers. The study therefore suggests perhaps an independent origin of the two components of oesophageal adenosquamous mixed cancer.
authors.affiliation: Laboratory of Molecular Oncology Centre for DNA Fingerprinting and Diagnostics (CDFD), Hyderabad, India.
authors.forename: Ramaswamy
authors.initials: R
authors.lastname: Pandilla
authors.forename: Viswakalyan
authors.initials: V
authors.lastname: Kotapalli
authors.forename: Swarnalata
authors.initials: S
authors.lastname: Gowrishankar
authors.forename: MohanaVamsy
authors.initials: M
authors.lastname: Chigurupati
authors.forename: Sujith
authors.initials: S
authors.lastname: Patnaik
authors.forename: Shantveer
authors.initials: S
authors.lastname: Uppin
authors.forename: Subramanyeshwar
authors.initials: S
authors.lastname: Rao
authors.forename: Narasimharaju
authors.initials: N
authors.lastname: Kalidindi
authors.forename: Sastry
authors.initials: S
authors.lastname: Regulagadda
authors.forename: Challa
authors.initials: C
authors.lastname: Sundaram
authors.forename: Mukta
authors.initials: M
authors.lastname: Srinivasulu
authors.forename: Anjayneyulu
authors.initials: A
authors.lastname: Vasala
authors.forename: Murali Dharan
authors.initials: MD
authors.lastname: Bashyam
mesh_terms: D000230:Adenocarcinoma / Q000235:genetics*; D052685:Alphapapillomavirus / Q000235:genetics; D002294:Carcinoma, Squamous Cell / Q000235:genetics*; D004273:DNA, Neoplasm / Q000235:genetics; D004279:DNA, Viral / Q000235:genetics; D004938:Esophageal Neoplasms / Q000235:genetics*; D017809:Fatal Outcome; D005260:Female; D018773:Genes, erbB-1 / Q000235:genetics; D016158:Genes, p53 / Q000235:genetics; D061809:Human Papillomavirus DNA Tests; D006801:Humans; D019656:Loss of Heterozygosity; D008297:Male; D053842:Microsatellite Instability; D008875:Middle Aged; D051153:Wnt Proteins / Q000235:genetics
chemical_list: D004273:DNA, Neoplasm; D004279:DNA, Viral; D051153:Wnt Proteins
keywords: Adenosquamous mixed cancers; EGFR; Wnt; esophageal adenocarcinoma; esophageal squamous cell carcinoma; p53